Method for controlling forest work machine and forest work machine
By using position data to guide the forest work machine's turning, the method addresses the challenge of maintaining optimal run distances, improving thinning quality and efficiency.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2026-03-26
AI Technical Summary
The challenge in forest thinning is accurately judging the distance between runs when operating a forest work machine, leading to either too large or too small distances, which affects the quality of thinning due to excessive or insufficient tree felling.
A method for controlling the forest work machine involves storing position information to create a set of points, forming a straight line representing the traveled route, and providing visual guidance on a display to ensure the machine turns onto a parallel, oppositely directed route at a predetermined distance, facilitating precise run formation.
This approach simplifies the operator's task of maintaining the correct distance between runs, enhancing the quality of thinning by optimizing tree felling and reducing unnecessary tree removal.
Smart Images
Figure FI2025050186_26032026_PF_FP_ABST
Abstract
Description
[0001] Method for controlling forest work machine and forest work machine
[0002] Background of the invention
[0003] The invention relates to a method for controlling a forest work machine and a forest work machine which comprises a boom and, at the end of the boom, a wood processing device suitable for at least tree felling.
[0004] When a forest is thinned out, poor-quality trees are removed out of the way of fast-growing trees in order for the fast-growing trees to get more growing space, nutrients and light. Additionally, good-quality trees that grow too densely can be removed. Modern machine thinning often utilizes a mobile forest work machine which comprises a boom and, at the end of the boom, a wood processing device suitable for at least tree felling. Said wood processing device can also comprises means required for processing the felled tree, that is, for removing branches and / or bark and for cutting the tree trunk into parts of preferred length.
[0005] In the thinning of forest taking place by means of a mobile forest work machine, the forest work machine is controlled to move along thinning paths. Said thinning paths are also called runs. The runs are routes that are substantially parallel but are travelled in turns into opposite directions, along with which, the forest work machine is controlled to move in a forest being thinned. During the first thinning of the forest, the runs are established in the forest in accordance with the method that the forest work machine is controlled to move in the forest when thinning it. During the second and possibly the next thinnings of the forest, it is possible to utilize the runs established during the first thinning of the forest, if preferred.
[0006] According to a thinning method, the preference is to establish the runs in the forest such that the distance between the runs is at least two times the reach of the forest work machine boom and the wood processing device at its end. In this case, the wood processing device can reach to thin the forest remaining between the runs but, at the same time, too many runs are not established, which would cause too much tree felling from the runs and thus weaken the quality of the thinning.
[0007] According to another thinning method, between the runs are established zones where the intensity of thinning differs from each other. Then, the intensity of thinning is arranged to differ from each other by zones such that the intensity of thinning is higher closer to the run and lower farther from the run. Furthermore, between the runs can remain a zone where thinning is not performed at all. In the thinning performed this way, there is a tendency to keep the distance of the runs from each other greater than two times the reach of the forest work machine boom and the wood processing device at its end. The distance of runs from each other can be set e.g. in a thinning plan.
[0008] A problem when performing an appropriate thinning is the turning of the forest work machine at the end of the run established by the already travelled route into the opposite direction such that the route travelled into the opposite direction in question is located roughly at a preferred distance from the previous route travelled into the opposite direction. Because in accordance with the above- mentioned thinning methods, the distance between the runs for the part of the largest modern forest work machines is typically at least about 20-22 metres, the correct judgement of the distance to be left between the runs is difficult particularly when the machine moves. In said turning situation of the forest work machine, the operator of the machine typically tries to turn the forest work machine too early or vigorously, thus aiming to ensure that the distance of the runs from each other will not become too large. However, this easily leads to a too small distance between the runs, which causes too much tree felling from the runs and thus weakens the quality of thinning.
[0009] Brief description of the invention
[0010] The object of the invention is to introduce a novel type of a method for controlling a forest work machine and a novel type of a forest work machine.
[0011] The solution according to the invention is characterised by what is disclosed in the independent claims.
[0012] The invention is based on controlling the travel of the forest work machine in its work environment for felling trees and locating the position of the forest work machine during the travel of the forest work machine. Position information describing the located positions of the forest work machine are stored in the control system of the forest work machine, whereby a piece of position information describing each located position of the forest work machine forms a point in a set of points formed by the position information describing located positions. To a limited set of points describing the located positions of the forest work machine is arranged a straight line which describes the route travelled by the forest work machine in its work environment. At least one visual guidance is produced to a display unit of the forest work machine to guide the turning of the forest work machine onto a route which is at a predetermined distance from, substantially parallel with and travelled substantially in the opposite direction from said route related to the straight line travelled by the forest work machine, and the forest work machine is controlled onto said route travelled substantially in the opposite direction.
[0013] The solution according to the invention makes it easier for the operator of the forest work machine to control the forest work machine to turn from the run of the already travelled route to the route to be travelled next such that the run determined by the route to be travelled next will be located substantially at said predetermined distance from the run determined by the route already travelled. Then, the run determined by the route to be travelled next will be located substantially at the intended distance from the run determined by the route already travelled.
[0014] A single run is thus determined based on the route that the forest work machine has travelled substantially into one direction. Said route can describe e.g. the middle of said run. A typical width of the run is about 4-4.5 metres. During said travel of the forest work machine, the forest around the forest work machine is thinned. Furthermore, it is also possible that trees have to be removed from the route of the forest work machine for forming said route and the run determined by it for the forest work machine. During thinning, a run network is formed in the forest, which comprises at least said runs travelled typically into opposite direction and a connecting run formed between them during the turning of the forest work machine. The run network can also comprise various additional runs intended for supplementing the felling or collecting of trees.
[0015] Some embodiments of the invention are presented in the dependent claims.
[0016] Brief description of the drawings
[0017] The invention will now be described in greater detail by means of preferred embodiments and with reference to the attached drawings, in which:
[0018] Figure 1 is a schematic diagonal top view of a forest work machine,
[0019] Figure 2 is a schematic view of a control system of a forest work machine and means related to it,
[0020] Figures 3a, 3b and 3c are schematic views of a work environment of a forest work machine and the travel of the forest work machine in its work environment,
[0021] Figures 4a and 4b schematically show an embodiment for controlling the turning of the forest work machine,
[0022] Figures 5a and 5b schematically show another embodiment for controlling the turning of the forest work machine, Figures 6a, 6b and 6c schematically show some examples for determining variables which describe the magnitude of the change of direction of the forest work machine, and
[0023] Figures 7a and 7b schematically show some examples of visual guidances for controlling the turning of the forest work machine.
[0024] For reasons of clarity, some embodiments of the invention are illustrated in the figures in a simplified form. Similar parts are indicated in the figures by the same reference numbers.
[0025] Detailed description of the invention
[0026] Figure 1 is a schematic diagonal top view of a harvester 1 which is a forest work machine wherein the solution described in this specification can be applied. The harvester 1 comprises a chassis 2 which forms at least part of a frame structure 3 of the harvester 1. The harvester 1 of Figure 1 is an articulated steer harvester, whereby the frame structure 3 of the harvester 1 comprises a front frame 3a and a rear frame 3b separate from each other which are connected by means of a joint between them. Into connection with the frame structure 3 of the harvester 1 are arranged moving means 4, by means of which, the harvester 1 may move in relation to its work surface or work environment. Said moving means 4 are wheels in Figure 1, but generally said moving means can comprise at least one of the following: wheels arranged on an axle, wheels arranged on a bogie, a track system or some other means known as such to provide the movement of the forest work machine and to possibly change the position and / or direction of the movement of the forest work machine in relation to its work surface or work environment.
[0027] The harvester 1 further comprises a power source 5. In the harvester 1 of Figure 1, the power source 5 is arranged to be supported by the rear frame 3b. The power source 5 can comprise e.g. a combustion engine, one or more electric motors and sets of batteries, and / or a generator or different combinations of these for generating the required power for providing the movement of the harvester 1 and for operating the devices arranged in the harvester 1.
[0028] The harvester 1 additionally comprises a cab 6. In the harvester 1 of Figure 1, the cab 6 is arranged to be supported by the front frame 3a. The cab 6 may be arranged foldably and / or rotatably in relation to the chassis 2. The cab 6 comprises a user interface 7, by means of which, the operator of the harvester 1 may control the drive of the harvester 1 and the devices arranged to the harvester 1. In Figure 1, said user interface 7, which will be described in more detail in connection with Figure 2, is shown very schematically. Generally, the user interface of the harvester 1 can comprise e.g. one or more manually-controllable control means, such as e.g. a joystick, and / or one or more foot-controllable control means, such as a pedal, and one or more display units. In addition to said control means, the control means can also comprise a pre-designed harvester work plan in the form of a runnable programme which is runnable by e.g. a harvester control unit 8 very schematically shown in Figure 1 for controlling the drive of the harvester and the devices arranged in it. The control unit 8, of which there can be more than one, is thus configured to control the operation of the forest work machine and the wood processing device to implement control measures performed by means of the user interface. Said control unit 8 can be e.g. a computer or some other device or means typically comprising a microprocessor or some other microcontroller.
[0029] The harvester 1 further comprises a boom 9. The boom 9 can be supported e.g. on the chassis 2 or a base connected to the chassis or some other part of the harvester frame or a part connected to the frame. The boom 9 may be arranged foldab ly and / or rotatably in relation to the chassis 2. At the outmost end of the boom 9, there is a harvester head 11 forming the wood processing device of the harvester 1, which head is connected to the boom 9 by means of a shackle 10.
[0030] The harvester 1 of Figure 1 constitutes a mobile forest work machine equipped with a wood processing device, which is intended, via the harvester head 11, for performing the felling of trees, delimbing and / or debarking the felled tree and cross-cutting the trunk of the felled tree into parts of preferred length. Alternatively, the mobile forest work machine equipped with a wood processing device can also be a combination of a forwarder and a harvester, whereby the forest work machine in question also comprises a load space for taking a load, typically parts of the trunk of the tree cross-cut to size, to be transported by the forest work machine. Furthermore, the mobile forest work machine equipped with a wood processing device may also be some other mobile forest work machine suitable for felling trees, such as e.g. an excavator with a wood processing device fixed to its boom.
[0031] Different from the example of Figure 1, the mobile forest work machine equipped with a wood processing device can also be a forest work machine solely suitable for felling trees. In this case, the wood processing device of the forest work machine only comprises means suitable for supporting and cross-cutting the trunk of the tree to be felled but not means required for processing the felled tree, such as delimbing and possibly also debarking the felled tree. Wood processing devices which are only applicable for felling a tree and not being capable of removing branches and possibly also bark from an already felled tree, are also called felling heads of a forest work machine to separate them from harvester heads of a forest work machine also suitable for further processing the felled tree.
[0032] The forest work machines of Figure 1 are typically forest work machines operating based on the active control of the operator of the forest work machine. However, it is also possible to apply the here presented solution in both semi-autonomously operating forest work machines, whereby the forest work machine can operate without the active control of the operator at least for some time, and in a substantially totally autonomously operating forest work machine, whereby the operator does not actively contribute to the control of the forest work machine operations without a special reason. The user interface 7 of the forest work machine can also be located separate from the forest work machine, whereby the control of the forest work machine is implemented by remote control. If the control of the forest work machine is totally implementable by remote control, the forest work machine does not necessarily include the cab 6.
[0033] Figure 2 schematically shows a control system 20 of a forest work machine and means related to it which can be used for controlling the turning of the forest work machine from the route travelled by the forest work machine onto a route located substantially at a specific distance from, substantially parallel with and substantially travelled into the opposite direction of the route. The routes travelled by the forest work machine determine the runs in the work environment of the forest work machine which runs can be utilized when performing the next thinnings. After the felling of the trees, a forest work machine used for collecting the trees, such as e.g. a forwarder, can utilize the same runs when collecting felled trees.
[0034] The control system 20 of Figure 2 comprises a control unit 21. In accordance with what is described in this specification, the control unit 21 is configured to produce control information to the operator of the forest work machine for controlling the turning of the forest work machine onto a route which is at a predetermined distance from, substantially parallel with and travelled substantially in the opposite direction from the route already travelled by the forest work machine. The control unit 21, of which there can be more than one, can be the same as the one or more control units 8 of the harvester 1 mentioned above. Alternatively, the control unit 21 can have been implemented as part of the control unit 8 of the harvester 1. The control unit 21 may also be a control unit physically separate from the control unit 8 of the harvester 1 but functionally configured to work together with the control unit 8 of the harvester 1. The control unit 21 can be e.g. a computer or some other device or means comprising a microprocessor or some other microcontroller that is obvious to those skilled in the art. The control unit 21 is configured to produce, via a programme saved to the control unit 21, based on measurement or imaging data received by the control unit 21 and / or data further determined based on them, control information for the operator of the forest work machine to guide the control of the forest work machine for turning the forest work machine onto a route which is at a determined distance from, substantially parallel with and travelled substantially in the opposite direction from the route travelled by the forest work machine.
[0035] With reference to the harvester 1 of Figure 1, the control unit 21 of the control system 20 of Figure 2 is configured to control the use of the harvester 1 via a control connection CO-1 and the use of the boom 9 and the harvester head 11 at its end via a control connection CO-9-11.
[0036] The control system 20 further comprises a user interface 7. The user interface 7 can comprise e.g. above-mentioned one or more manually controllable control means 7a, such as e.g. a joystick, and / or one or more foot controllable control means 7b, such as e.g. a pedal, for controlling the operation of the forest work machine and the wood processing device. Furthermore, the user interface 7 comprises one or more display units 7c for displaying visually-presentable information. The display unit 7c is configured to present at least graph! cally-presentable information. The display unit 7c may comprise e.g. a display of a monitor or computer screen type, a head-up display to be reflected on the window of the forest work machine or a display formed by a virtual reality headset.
[0037] The user interface 7 can also comprise means for data presentable by means of voice, such as e.g. for producing one signal tone or several signal tones different from each other. The user interface 7 can also comprise means for receiving control commands presetable by means of voice. The user interface 7 is connected to the control unit 21 by a data transfer connection DTC7.
[0038] The control system 20 of Figure 2 is also connected with at least one positioning means 30 for locating the position of the forest work machine in its work environment. The positioning means 30 is connected to the control unit 21 by a data transfer connection DTC30. The positioning means 30 can comprise e.g. one locator 31 utilizing a satellite positioning system, such as e.g. a GPS system, which locator is configured to receive a required number of time and navigation signals sent by satellites belonging to the satellite positioning system in order to determine the position of the forest work machine in its work environment. In addition to or instead of the locator 31 utilizing the satellite positioning system, the positioning means 30 can comprise e.g. a locator 32 based on camera, Lidar or some other technology which can determine based on imaging the position of the forest work machine in its work environment in relation to one or more reference point selected from the work environment. Alternatively, the locator 32 can specify the position information of the forest work machine acquired by means of the satellite positioning system based on the determined position of the forest work machine in relation to one or more reference points.
[0039] The positioning system produces a set of points SOP, in which set of points SOP, a piece of information describing each located position of the forest work machine forms one point. The position information describing the located positions of the forest work machine can be saved to the control system 20 of the forest work machine, e.g. to a memory unit 22 arranged as part of the control unit 21, such as schematically shown in Figure 2, or to a memory unit separate from the control unit 21 but still functionally connected to it. The position information describing the position of the forest work machine is configured to describe the position of a specific selected part of the forest work machine in the work enviroment. With reference to harvester 1 of Figure 1, said specific part of the forest work machine can be selected e.g. the middle of the front frame 3a in the horizontal plane of the front frame 3a, the middle of the rear frame 3b in the horizontal plane of the rear frame 3b, or the position of the joint connecting the front frame 3a and the rear frame 3b in the forest work machine.
[0040] Figures 3a, 3b and 3c schematically show a work enviroment WE of the forest work machine and the travel of the forest work machine therein. Said forest work machine can be e.g. the harvester 1 of Figure 1. Figures 3a, 3b and 3c schematically show the travel of the forest work machine along a first route LR1 to the left, the turning of the forest work machine onto a second route LR2 which is at a predetermined distance from, substantially parallel with and travelled substantially in the opposite direction from the first route LR1 and the travel of the forest work machine further along the second route LR2 to the right. The preferred predetermined distance D of said second route LR2 from said first route LR1 can be e.g. a distance determined based on the combined reach of the forest work machine boom and the wood processing device at its end or a distance set in the thinning plan. According to the first alternative, the preference is to establish said routes in the forest such that the distance between the routes is at least two times the reach of the forest work machine boom and the wood processing device at its end. In this case, the wood processing device reaches to thin the forest remaining between said routes. For the largest modern forest work machines, said distance is thus typically about 20-22 metres.
[0041] According to the latter alternative, the distance between said routes can also be greater than double the reach of the forest work machine boom and the wood processing device at its end. Then, between the routes can remain a zone where thinning is not performed at all.
[0042] When the forest work machine travels along said routes in the work environment WE, trees are thinned on both sides of the forest work machine by removing poor-quality trees out of the way of good-growth trees. In the thinning, it is also possible to remove good-quality trees that grow too densely. In Figures 3a, 3b and 3c, the trees that are left standing are shown by circles open from inside and, in places, with designation ST, and the removed trees are shown by circles including cross-cut lines inside and, in places, with designation RT.
[0043] In the schematic situation in Figure 3a, the forest work machine is starting the thinning and it is intended to travel along the first route LR1 on the left seen in Figure 3a. In the schematic situation in Figure 3b, the forest work machine has approached the edge of a stand marked for cutting to be thinned and started to turn towards the second route running from the left to the right seen in Figure 3b. In the schematic situation in Figure 3c, the forest work machine has already turned to the second route LR2 and travelled along it for some time from the left to the right seen in Figure 3c. It should be noted in connection with Figures 3a, 3b and 3c that, before performing the first thinning of the forest, there are no specific routes in the forest along with which the forest work machine should travel when performing thinning but the routes in question are formed during the thinning work. The routes formed in the forest and the runs determined by these routes are either not typically straight but they wind somewhat due to trying to avoid various fixed obstacles, such as large stones and trees to be left standing. Usually, trees must also be felled to form the route for the forest work machine.
[0044] Figure 4a schematically shows a method for controlling the turning of a forest work machine of the kind shown in Figures 3a, 3b, 3c from its first route LR1 to a second route LR2 which is at a predetermined distance from it, substantially parallel with it and substantially driving in the opposite direction from it. Figure 4b schematically shows a correspondingly configured control system 20, particularly a control unit 21. According to the solution of Figures 4a and 4b, the travel of the forest work machine in its environment is controlled for felling trees, the position of the forest work machine is located during the travel of the forest work machine, position information describing the located positions of the forest work machine are stored to the control system of the forest work machine, whereby a piece of position information describing each located position of the forest work machine forms a point in a set of points formed by the pieces of position information describing the located positions, a straight line is arranged to a limited set of points describing the located positions of the forest work machine to describe a route travelled by the forest work machine in its work environment, at least one visual guidance is produced to the display unit of the forest work machine to guide the turning of the forest work machine onto a route which is at a predetermined distance from, substantially parallel with and travelled substantially in the opposite direction from the route travelled by the forest work machine related to said straight line, and the forest work machine is controlled to turn onto said route which is travelled substantially in the opposite direction.
[0045] With reference to Figures 2, 3a-3c, 4a, and 4b, the travel of the forest work machine is controlled, by the operator of the forest work machine either from the cab 6 or remotely, in the work environment WE for felling trees RT. During the travel of the forest work machine, the position of the forest work machine is located by a locator 30. Figure 3b shows the located positions of the forest work machine on the first route LR1 with points designated by LL. Said position information describing the located positions LL of the forest work machine are stored in the control system 20 of the forest work machine, such as e.g. in a memory unit 22, whereby a piece of position information describing each located position LL of the forest work machine forms a point in a set of points SOP formed by the position information describing located positions LL. The locating of the position of the forest work machine will be depicted later in more detail.
[0046] During the travel of the forest work machine, a straight line SL is arranged in the limited set of points describing the located positions LL of the forest work machine by the control system 20, in practice in the control unit 21 (Figure 3b). The straight line SL describes the first route LR1 travelled by the forest work machine in its work environment at a section corresponding said points. The arrangement of the straight line SL to the points describing the located positions LL of the forest work machine will be depicted later in more detail. For controlling the turning of the forest work machine onto a route, that is, the second route LR2, which is at a predetermined distance D from, substantially parallel with and travelled substantially in the opposite direction from the route travelled by the forest work machine related to said straight line SL, that is, the first route LR1, the control system 20, in practice the control unit 21, produces to the display unit 7c at least one visual guidance VG for guiding the turning of the forest work machine onto said second route LR2. In the embodiment of Figure 3b, said visual guidance VG is a guidance, which is graphically presented and of the shape of an arrow, substantially at a distance D from the straight line SL related to the first route LR1, which guidance shows the position and direction of the second route LR2 in relation to the first route LR1. The guidance of the turning of the forest work machine and various visual guidances VG are depicted later in more detail.
[0047] When to the display unit 7c is produced at least one visual guidance VG to guide the turning of the forest work machine onto said second route LR2, the operator of the forest work machine can, by means of said guidance, control the forest work machine to turn onto said second route LR2 such that said second route LR2 will be located substantially at said predetermined distance from the first route LR1. Then, the second route LR2 will be located substantially at an intended distance from the first route LR1 such that the intended thinning is achievable.
[0048] With reference to the above-mentioned location of the position of the forest work machine in the work environment WE, the position of the forest work machine is determined at specific time intervals according to an embodiment. In this embodiment, the position of the forest work machine can be determined e.g. with the intervals of 5-30 seconds. In this embodiment, the position of the forest work machine in terms of time can be determined very accurately. However, when the forest work machine stays in place for longer time intervals e.g. due to the forest work machine being able to thin several trees without moving from its place, a lot of position information describing the located positions LL of the forest work machine can be accumulated from the one and the same position of the forest work machine. Additionally, when the forest work machine travels, the relation of the located positions LL of the forest work machine to the distance travelled can vary based on the travel speed of the forest work machine. For example due to these reasons, the arrangement of the straight line SL in a limited set located positions LL of the set of points SOP describing the located positions LL might require mathematical filtering or selection measures focused on the limited set in question before arranging the straight line SL to the limited set of located positions LL of the forest work machine in question.
[0049] According to another embodiment related to the location of the position of the forest work machine, the position of the forest work machine can be determined locally by set intervals. This embodiment is also schematically shown in Figure 3b and therein the position of the forest work machine is determined in relation to the distance travelled by the forest work machine by set intervals. Said set interval can be selected e.g. between 1-5 metres. Said set interval can then be e.g. 2.5 metres. In this embodiment, the located positions LL of the forest work machine are only accumulated when the forest work machine moves, whereby the number of accumulated located positions LL remains reasonable. In this case, the arrangement of the straight line SL to a limited set of the set of points SOP describing the located positions LL of the forest work machine does not necessarily require, before arranging the straight line SL, any mathematical filtering or selection measures focused to the limited set of located positions LL in question irrespective of the limited set of located positions LL in question was to comprise such extra or unnecessary located positions LL of the forest work machine which have been collected as a result of a short move backwards of the forest work machine.
[0050] The straight line SL can be arranged to a limited set of located positions LL utilizing e.g. the method of least squares.
[0051] According to an embodiment, as shown e.g. in Figure 3b, when arranging the straight line SL to a limited set of points describing the located positions LL of the forest work machine, the straight line SL is left unarranged to a number of points describing the newest located positions LL in relation to the distance travelled and to a number of points describing the oldest located positions LL in relation to the distance travelled. Said limitation can ensure e.g. the fact that said arrangement of the straight line SL does not utilize the located positions collected during the turn performed at the end of the route of the forest work machine, which might lead to an incorrect positioning of the visual guidance VG in relation to the route related to the straight line SL in question. According to an embodiment, the straight line SL is arranged to such a set of located positions LL of the forest work machine which have been collected 5-50 m before starting the turning of the forest work machine from the current route to the next route to be travelled in the opposite direction.
[0052] The visual guidance VG used for controlling the turning of the forest work machine is produced to the display unit 7c when the turning of the forest work machine is started from the current route to the next route to be travelled in the opposite direction. According to an embodiment, the visual guidance VG is produced to the display unit 7c on the forest work machine operator’s initiative. In this embodiment, the control system 20 can comprise e.g. an icon shown in the display unit 7c which the operator of the forest work machine can activate when starting to turn the forest work machine to the next route travelled in the opposite direction when the forest work machine approaches the edge of the stand marked for cutting to be thinned on the current route. As a response to the activation of said icon, the control system 20 produces for the operator to the display unit 7c at least one visual guidance VG to guide the turning of the forest work machine to the next route which is located at a predetermined distance D and travelled in the opposite direction.
[0053] According to an embodiment, the visual guidance VG is produced to the display unit 7c automatically by the control system 20. In this embodiment, the control system 20 automatically detects such a deviation of the position of the forest work machine from the route related to the straight line SL which deviation cannot be interpreted as a change of direction within the ordinary route. A such an embodiment is schematically shown in Figures 5a and 5b. Figure 5a schematically shows a method for controlling the turning of a forest work machine of the kind shown in Figures 3a-3c from its first route LR1 to a second route LR2 which is at a predetermined distance from it, substantially parallel with it and substantially driving in the opposite direction from it, wherein the visual guidance VG is produced to the display unit 7c automatically by the control system 20. Figure 5b schematically shows a correspondingly configured control system 20, particularly a control unit 21. The embodiment of Figure 5a follows for its first part the embodiment of Figure 4a but is different for its last part from the embodiment of Figure 4a such that, in the embodiment of Figure 5a, the magnitude of the change of direction taking place in the travel direction of the forest work machine is determined in relation to said straight line when the forest work machine travels in its work environment, the magnitude of the change of direction of the travel direction of the forest work machine is compared to a limit value set for the magnitude of the change of direction and, when the magnitude of the change of direction of the travel direction of the forest work machine exceeds the limit value set for the change of direction, said at least one visual guidance is automatically produced to the display unit of the forest work machine and the forest work machine is controlled to turn onto said route which is travelled substantially in the opposite direction. In the embodiment of Figures 5a and 5b, the located positions LL of the forest work machine produced by the locator 30 are stored to the control system 20 of the forest work machine, where they form a set of points SOP describing the located positions LL of the forest work machine. Of the set of points SOP describing the located positions LL of the forest work machine, a limited set LSOP of located positions LL of the forest work machine is selected to which the straight line SL is arranged. The control system 20, particularly the control unit 21, is further configured to determine a magnitude ACOF of the change of direction taking place in the travel direction of the forest work machine by comparing a deviation of the newest located positions LL of the forest work machine received from the locator 30 in relation to said straight line SL. The control system 20, and thus particularly the control unit 21, is additionally configured to compare the determined magnitude ACOF of the change of direction of the forest work machine to a limit value ACOFiimit set to the magnitude ACOF of the change of direction. When the magnitude ACOF of the change of direction exceed the limit value ACOFiimit set to the magnitude of the change of direction ACOF, the control system 20, and particularly the control unit 21, is configured to produce to the display unit 7c at least one visual guidance VG to guide the turning of the forest work machine to a route which is travelled substantially in the opposite direction.
[0054] Figures 6a, 6b and 6c schematically show some alternatives for determining to some possible variables describing the magnitude ACOF of the change of direction of the forest work machine automatically to indicate the change of direction being a result of trying to turn the forest work machine onto the route which is travelled substantially in the opposite direction. Figures 6a, 6b and 6c show the straight line SL and the forest work machine, such as e.g. the harvester 1 of Figure 1, in its travel direction having turned to the right in relation to the straight line SL (upwards in the plane of Figure 6).
[0055] In Figure 6a, designation X shows a straight line parallel with the longitudinal central axis of the forest work machine and designation ANG shows an angle between said straight line X parallel with the longitudinal central axis and the straight line SL. In an articulated steer harvester 1 of the kind shown in Figure 1, said straight line X parallel with the central axis can be e.g. a straight line parallel with the longitudinal central axis of the front frame 3a, a straight line parallel with the longitudinal central axis of the rear frame 3b or a straight line parallel with a direction selected from between the directions of the longitudinal axes of the front frame 3a and the rear frame 3b. If the absolute value of said angle ANG is greater that a limit value set for it, the control system 20 interprets that the operator of the forest work machine turns the forest work machine so strongly that the purpose is to control the forest work machine to turn onto the next route which is travelled substantially in the opposite direction. The absolute value of the set limit value for said angle ANG can be e.g. 40-60 degrees.
[0056] In Figure 6b, line segments designated by SCI and SC2, directed to the side and the rear in relation to the longitudinal central axis of the forest work machine, limit a sector SC defined behind the forest work machine. If the line segment defining the edge of said sector in the turning direction (line segment SCI in Figure 6b) crosses the straight line SL when the forest work machine is turning, such as is schematically shown in Figure 6b, the control system 20 interprets that the operator of the forest work machine turns the forest machine with the purpose to control the forest machine to turn onto the next route which is travelled substantially in the opposite direction. The size of said sector can be e.g. ± 40 - ±60 degrees in relation to the selected longitudinal central axis of the forest work machine.
[0057] In Figure 6c, there is a point defined for the front part of the forest work machine, in the case of the harvester 1 of Figure 1 e.g. for the middle of the front frame 3a in the horizontal plane of the front frame 3a, in relation to which the position of the forest work machine in the work environment WE is determined. Said point is located at a distance IS from the straight line SL when turning the forest work machine. If the magnitude of said distance IS is greater that a limit value set for it, the control system 20 interprets that the operator of the forest work machine turns the forest work machine with the purpose to control the forest work machine to turn onto the next route which is travelled substantially in the opposite direction. A limit value set for said distance can be e.g. 5-7 metres from the middle of the run, if the width of the run is the typical 4-4.5 metres.
[0058] Figures 6a, 6b and 6c and the description related them only show some alternatives for determining the magnitude ACOF of the change of direction of the forest work machine based on the deviation of the position in the route of the forest work machine related to the straight line SL. In addition to what is presented in Figures 6a, 6b and 6c and the description related to them, also other alternatives for determining the magnitude ACOF of the change of direction of the forest work machine can be used.
[0059] Figures 7a and 7b show some examples of visual guidances which can be used for controlling the turning of the forest work machine from the route LR1 related to the straight line SL travelled by the forest work machine onto the route LR2 to be travelled in the opposite direction. Figures 7a and 7b show the display unit 7c and an image of the turning forest machine produced by the control system 20, particularly the control unit 21. The position of the forest work machine on the display of the display unit 7c can be updated e.g. at specific time intervals based on the turning of the forest work machine. Furthermore in Figures 7a and 7b, on the display of the display unit 7c have been produced a first visual guidance VG1 and a second visual guidance VG2 which are graphical elements produced onto the display of the display unit 7c which both are formed of a set of display points of the display of the display unit 7c. In this context, it should be noticed that the production of an image of the forest work machine and / or a map of the work environment of the forest work machine and / or a route travelled / to be travelled onto the display is not at all necessary, nor is the production of two visual guidances, but the guidance of the turning of the forest work machine can be implemented by only one visual guidance produced onto the display of the display unit 7c. Figures 7a and 7b also show for reasons of clarity a part of the route LR1 already travelled by the forest work machine by dashed lines and a part of the next route LR2 to be travelled by the forest work machine and the straight line SL related to the route already travelled by the forest work machine, but the production of them onto the display of the display unit 7c is thus not necessary either.
[0060] According to an embodiment of a visual guidance, at least one visual guidance indicates the target of the turning of the forest work machine to control it to the route to be travelled in the opposite direction. The target of the turning of the forest work machine can be indicated by at least one of the following characteristics: a starting point of the route LR2 to be travelled in the opposite direction, a directional pointer for the position and direction of the route LR2 to be travelled in the opposite direction, a relative share of a realized turn from the turn implementing the predetermined distance, or a distance from the straight line SL of the route LR1 travelled by the forest work machine.
[0061] In the examples of Figures 7a and 7b, the first visual guidance VG1 is a possible guidance to indicate said target of the turning of the forest work machine. In the examples of Figures 7a and 7b, the first visual guidance VG1 is implemented by a graphical element of triangular shape, one vertex of which can be produced onto the display of the display unit 7c to point at the starting point of the route LR2 to be travelled in the opposite direction, or said graphical element of triangular shape can be produced on the display of the display unit 7c as a directional pointer to point the position and direction of the route to be travelled in the opposite direction. Then, the starting point or position and direction of said route LR2 to be travelled in the opposite direction are some characteristics describing the target of the turning of the forest work machine which can be indicated by the first visual guidance VG1.
[0062] The first visual guidance VG1 can be additionally or alternatively configured to indicate the relation share of the realized turn of the forest work machine from a turn implementing the predetermined distance. In this embodiment, the number and / or characteristics of the display points of the display unit 7c forming the visual guidance can be altered in relation to the turn of the forest work machine implementing the predetermined distance, which can be determined based on a deviation between the located positions LL of the forest work machine and the target of the turn of the forest work machine shown by the visual guidance. With reference e.g. to the triangular first visual guidance VG1 shown in Figures 7a and 7b, the number of display points of the display unit 7c forming said first visual guidance VG1 can be altered e.g. by changing the size of said triangular shape. In this case, according to an example, the size of said graphical element can be configured to increase the bigger the bigger the share of the realized turn of the forest work machine to the turn implementing the predetermined distance is. Furthermore, the number of the first visual guidance VG1 mentioned as an examples can be altered by activating the status of display point of the display unit being inside the edges of said graphical element to correspond the status of the display points forming the edges of the graphical element, which can also be interpreted as altering the characteristics of the display points of the display unit forming said graphical element. Then, the statuses of the display points inside the edges of said graphical element can be activated on the basis on what the share of the realized turn of the forest work machine is from the turn implementing the predetermined distance. This changes the visual outlook of the graphical element in question such that the area limited by the edges of the graphical element seems to fill up the more the greater the share of the realized turn of the forest work machine is from the turn implementing the predetermined distance.
[0063] Additionally according to an example, the status of the display points forming the graphical element can be changed by altering the colour or tone produced by the display points forming the graphical element in question. In this case, the colour or tone produced by the display point forming the graphical element in question can be altered from one colour or tone to another in the share of the greater the share of the realized turn of the forest work machine is from the turn implementing the predetermined distance.
[0064] According to an alternative, the target of the turning of the forest work machine indicated by the visual guidance can show the distance from the straight line SL describing the route LR1 the forest work machine has already travelled. In this embodiment, it is possible to produce onto the display of the display unit 7c a straight line of the kind e.g. designated by D in Figure 3 to indicate the distance of the next route LR2 to be travelled by the forest work machine from the straight line SL describing the route LR1 that the forest work machine has already travelled.
[0065] According to an embodiment of a visual guidance, at least part of the display points of the display unit forming the graphical element corresponding the visual guidance is controlled to form a vertex shape to point at the target of the turning of the forest work machine for controlling the turning of the forest work machine onto said route to be travelled in the opposite direction. In this embodiment, which is presented in Figures 7a and 7b by means of an example with a second visual guidance VG2, the display points of the display unit forming the graphical element can be activated or turned off for forming the vertex shape in question to the visual guidance VG2. In the example of Figure 7a, the forest work machine has been turned too little for the forest work machine to turn to the next route LR2 to be travelled, whereby the second visual guidance VG2 shows by its vertex shape pointing to the right seen in Figure 7a the direction where the forest work machine should be turned for turning it onto the next route LR2 to be travelled. In the example of Figure 7b, the forest work machine has been turned too much for the forest work machine to turn to the next route LR2 to be travelled, whereby the second visual guidance VG2 shows by its vertex shape pointing to the right seen in Figure 7b the direction where the forest work machine should be turned for turning it onto the next route LR2 to be travelled. In the examples of Figures 7a and 7b, the vertex shape of the second visual guidance VG2 thus also forms a characteristic to indicate the target of the turning of the forest work machine. In connection with the second visual guidance VG2, it is also possible to indicate the target of the turning of the forest work machine by altering the number and / or characteristics of the display points of the display unit forming the graphical element corresponding to the second visual guidance VG2 during the turning of the forest work machine in relation to the turning of the forest work machine implementing the predetermined distance, such as presented above in connection with the first visual guidance VG1. Figures 7a and 7b schematically show only some possible examples of the visual implementations of a visual guidance. In practice, the outlook of the graphical element forming the visual guidance can be implemented in many different ways, whereby it is also possible to store to the control system 20 several visual guidance of different outlooks. In this case, the operator of the forest work machine can select such a visual guidance that they see the most informative for controlling the forest work machine onto the next route LR2 to be travelled.
[0066] In addition to a visual guidance, it is also possible to utilize sound guidance. Then, the control system 20 of the forest work machine can e.g. produce a sound signal the frequency of which increases in accordance with the closer the turning of the forest work machine is to the target set to it. When the forest work machine has turned to the target set to it, that is, turned onto the next route to be travelled, said sound signal can be continuous.
[0067] According to an embodiment, the forest work machine comprises at least one imaging means for imaging the work environment of the forest work machine. Said at least one imaging means is schematically shown in Figure 2 by designation 32, and some of its possible embodiments were already described above in connection with the location of the position of the forest work machine. Furthermore according to this embodiment, when the magnitude of the change of direction of the travel direction of the forest work machine exceeds a limit value set for the magnitude of the change of direction, the work environment of the forest work machine is imaged via a control system configured for the purpose and said at least one imaging means, a turning route is determined for the forest work machine via the control system based on said imaging of the work environment, which route implements the turning of the forest work machine onto the route to be travelled substantially in the opposite direction, and a graphical description is produced via the control system to the display unit of the forest work machine on the determined turning route to guide the turning of the forest work machine onto the route to be travelled substantially in the opposite direction.
[0068] In the embodiment described above, the work environment of the forest work machine is thus imaged and, based on said imaging, a graphically produceable turning route is determined on the display of the display unit, in accordance with which, when turning the forest work machine, the forest work machine will turn onto the route to be travelled substantially in the opposite direction. Said turning route can be determined e.g. such that as small as possible number of trees have to be felled in order to form said turning route if there is not enough space between the trees for forming the turning route without felling trees. When determining said turning route, it is possible to consider the typically larger turning radius of the forest work machine used for collecting felled trees, whereby the requirement of felling trees possibly due to said larger turning radius can be primarily directed to such trees that are intended to be felled in the thinning. Naturally, the same principle for implementing the turning route enabled by the larger turning radius can be utilized in connection with thinning performed without said imaging means.
[0069] According to an embodiment, a route following the turning of the forest work machine to be travelled substantially in the opposite direction is determined via a control system configured for the purpose, which route runs substantially at a distance from and parallel with the route travelled by the forest work machine related to said straight line, and a graphical description of said route travelling substantially in the opposite direction is produced via the control system to the display unit of the forest work machine to guide the controlling of the forest work machine along the determined route to be travelled substantially in the opposite direction. In this embodiment, a graphical description is thus produced to the display unit of the forest work machine on the route following the turning of the forest work machine to be travelled substantially in the opposite direction to guide the controlling of the forest work machine on the next route to be travelled. From the effect of said guidance, it is possible to prevent the controlling of the forest work machine too close to or too far away from the route travelled already before the turning.
[0070] According to an embodiment, the control system of the forest work machine comprises a map describing the work environment of the forest work machine stored in the control unit, and the control system is configured to produce said map to the display unit and the control system is configured to produce said visual guidance to the map presented in the display unit. According to this embodiment, with reference to Figure 2, a map MAP describing the work environment WE of the forest work machine is stored to the control unit 21 of the control system 20 or to a memory in connection with it. Said map can comprise e.g. contour curves describing the height variations in the work environment WE of the forest work machine and the position of largest erratic boulders etc. in the work environment WE of the forest work machine. When the control system 20 produces said map MAP and visual guidance VG onto the display of the display unit 7c, the operator of the forest work machine can turn the forest work machine utilizing the data on the map MAP to travel from the route the forest work machine has already travelled onto the next route to be travelled as shown by the visual guidance VG. According to an embodiment, the control system of the forest work machine comprises a map describing the work environment of the forest work machine stored in the control unit which includes a work area limited to the forest work machine, and the control system of the forest work machine comprises at least one imaging means for imaging the work environment of the forest work machine and the control system is configured to update the contents of the map via said at least one imaging means based on information produced from the work environment of the forest work machine. According to this embodiment, with reference to Figure 2, a map MAP describing the work environment WE of the forest work machine is stored to the control unit 21 of the control system 20 or to a memory in connection with it. To the map MAP is further limited a work area determined for the forest work machine which is schematically shown in Figure 3 by an outline shown by a dashed line and designation WA. Additionally, the forest work machine comprises at least one imaging means 32 for imaging the work environment WE of the forest work machine, whereby the control system 20 and particularly the control unit 21 can be configured to update the contents of the map MAP via said at least one imaging means 32 based on information produced from the work environment WE of the forest work machine. To a map base 21, it is possible to update e.g. the position of runs determined by the routes travelled by the forest work machine and positions of trees left standing and trees felled during the thinning, and possibly also height and thickness information of the trees left standing. The information in question can be utilized for e.g. estimating the time of the next thinning or final felling or planning its implementation.
[0071] When the borders of the work area WA are known, the control system can guide to start the turn at a suitable distance when approaching the border of the work area. In addition to or instead of guiding, the control system can also assist in the turning or perform the turning automatically.
[0072] Those skilled in the art will find it obvious that, as technology advances, the basic idea of the invention may be implemented in many different ways. The invention and its embodiments are thus not restricted to the examples described above but may vary within the scope of the claims.
Claims
Claims1. A method for controlling a forest work machine, which forest work machine comprises a boom and, at the end of the boom, a wood processing device suitable at least for felling trees, a control system which comprises at least one control unit and a user interface, which user interface comprises control means connected to the control unit for controlling the operation of the forest work machine and the wood processing means and at least one display unit for displaying visually presentable information, and which control unit is configured to control the operation of the forest work machine and the wood processing device for implementing control measures performed by means of the user interface, and at least one locator for positioning the forest work machine in its work environment, and in which method controlling the travel of the forest work machine for felling trees, locating the position of the forest work machine during the travel of the forest work machine, storing position information describing the located positions of the forest work machine in the control system of the forest work machine, whereby a piece of position information describing each located position of the forest work machine forms a point in a set of points formed by the position information describing located positions, arranging to a limited set of points describing the located positions of the forest work machine a straight line which describes the route travelled by the forest work machine in its work environment, determining the magnitude of the change of direction taking place in the travel direction of the forest work machine in relation to said straight line when the forest work machine travels in its work environment, comparing the magnitude of the change of direction of the forest work machine to a limit value set for the magnitude of the change of direction, when the change of direction of the travel direction of the forest work machine exceeds the limit value set for the magnitude of the change of direction, producing automatically to the display unit of the forest work machine at least one visual guidance to guide the turning of the forest work machine onto a route which is at a predetermined distance from, substantially parallel with and travelledsubstantially in the opposite direction from said route related to the straight line travelled by forest work machine controlling the forest work machine to turn onto said route travelling substantially in the opposite direction.
2. A method according to claim 1, characterized by determining the magnitude of the change of direction taking place in the travel direction of the forest work machine based on a deviation of the position of the forest work machine from said straight line.
3. A method according to any one of the preceding claims, characterized by, when arranging the straight line to the points describing the located positions of the forest work machine, leaving unarranged the straight line to a number of the points that describe the newest and the oldest positions in relation to the distance travelled.
4. A method according to any one of the preceding claims, characterized by indicating by at least one visual guidance the target of the turning of the forest work machine for controlling the forest work machine onto said route to be travelled into the opposite direction.
5. A method according to claim 4, characterized by indicating the target of the turning of the forest work machine by said visual guidance at least one of the following characteristics: a starting point of the route to be travelled in the opposite direction, a directional pointer for the position and direction of the route to be travelled in the opposite direction, a relative share of a realized turn from the turn implementing the predetermined distance, or a distance from the straight line of the route travelled by the forest work machine.
6. A method according to any one of the preceding claims, characterized by producing said visual guidance by forming to the display unit a graphical element which is formed of a set of display points of the display unit, and by altering the number and / or characteristics of the display points forming the graphical element during the turning of the forest work machine in relation to the turning of the forest work machine implementing the predetermined distance.
7. A method according to claim 6, characterized by controlling at least part of the display points of the display unit forming said graphical element to form a vertex shape to point at the target of the turning of the forest work machine to guide the turning of the forest work machine onto said route to be travelled in the opposite direction.
8. A method according to any one of the preceding claims, characterized by said predetermined distance from said route related to the straight line travelled by the forest work machine being determined by the reach of the boom of the forest work machine and the wood processing device at its end or being a distance set in the thinning plan.
9. A forest work machine comprising a boom and, at the end of the boom, a wood processing device suitable at least for felling trees, a control system which comprises at least one control unit and a user interface, which user interface comprises control means connected to the control unit for controlling the operation of the forest work machine and the wood processing means and at least one display unit for displaying visually presentable information, and which control unit is configured to control the operation of the forest work machine and the wood processing device for implementing control measures performed by means of the user interface, and at least one locator for positioning the forest work machine in its work environment, and which control system is configured to control in accordance with control measures implemented with control means the travel of the forest work machine in its work environment for felling trees, locate via said at least one locator the position of the forest work machine during the travel of the forest work machine, store position information describing the located positions of the forest work machine in the control system of the forest work machine, whereby a piece of position information describing each located position of the forest work machine forms a point in a set of points formed by the position information describing located positions, arrange to a limited set of points describing the successive located positions of the forest work machine a straight line which describes the route travelled by the forest work machine in its work environment, determine the magnitude of the change of direction taking place in the travel direction of the forest work machine in relation to said straight line when the forest work machine travels in its work environment, compare the magnitude of the change of direction of the forest work machine to a limit value set for the magnitude of the change of direction, andwhen the change of direction of the travel direction of the forest work machine exceeds the limit value set for the magnitude of the change of direction, produce automatically to the display unit of the forest work machine at least one visual guidance to guide the turning of the forest work machine onto a route which is at a predetermined distance from, substantially parallel with and travelled substantially in the opposite direction from said route related to the straight line travelled by forest work machine.
10. A forest work machine according to claim 9, characterized in that the control system of the forest work machine is configured to determine the magnitude of the change of direction taking place in the travel direction of the forest work machine based on a deviation of the position of the forest work machine from said straight line.
11. A forest work machine according to any one of claims 9-10, characterized in that, when arranging the straight line to the points describing the located positions of the forest work machine, the control system is configured to leave unarranged the straight line to a number of the points that describe the newest and the oldest positions in relation to the distance travelled.
12. A forest work machine according to any one of claims 9-11, characterized in that said visual guidance is a graphical element to be produced to the display unit which is formed of a set of display points of the display unit, and that during the turning of the forest work machine, the control system is configured to alter the number and / or characteristics of the display points forming the graphical element in relation to the turning of the forest work machine implementing the predetermined distance.
13. A forest work machine according to claim 12, characterized in that the control system is configured control at least part of the display points of the display unit forming said graphical element to form a vertex shape to point at the target of the turning of the forest work machine to guide the turning of the forest work machine onto said route to be travelled in the opposite direction.
14. A forest work machine according to any one of claims 9-13, characterized in that the control system of the forest work machine comprises a map describing the work environment of the forest work machine stored in the control unit, and that the control system is configured to produce said map to the display unit and thatthe control system is configured to produce said visual guidance to the map presented in the display unit.
15. A forest work machine according to any one of claims 9-14, characterized in that the control system of the forest work machine comprises a map de- scribing the work environment of the forest work machine stored in the control unit in which is determined a work area for the forest work machine, and that the control system of the forest work machine comprises at least one imaging means for imaging the work environment of the forest work machine, and that the control system is configured to update the contents of the map based on information produced from the work environment of the forest work machine via said at least one imaging means.